Android mascots are lined up in the demonstration area at the Google I/O Developers Conference in the Moscone Center in San Francisco, California, May 10, 2011. REUTERS/Beck Diefenbach

The latest firmware from Google arrived in Nexus devices October last year, so it is not surprising that HTC and Moto phone users are asking about the launching of Android Marshmallow (Android M) on devices under Verizon, Sprint, AT&T, T-Mobile and US Cellular.

Let's start with Android M on HTC devices. Last month, HTC's VP for product management Mo Versi announced via Twitter that HTC One M9 users under Verizon and T-Mobile are set to receive Android M. Given that the rollout is slow and gradual, some users might receive the update in the next few days.

For One M9 users under AT&T, on the other hand, they have to wait for little a longer. Tech Times reported the mobile carrier had encountered some technical issues and will release the Android M upgrade shortly.

The unlocked version of HTC A9 in Canada is scheduled to receive Android M, HTC's product manager Leon Rosenzwaig revealed on Twitter. In addition, Canadian telecommunications companies Sasktel, Rogers, Videotron and Wind Mobile announced that they have started to roll out the Marshmallow upgrade for their subscribers. HTC One M8 & M9 under Telus also launched the upgrade as well.

For HTC M8 owners, T-Mobile and Verizon approved the release of the Android M update, Versi announced. The said devices will start receiving the software via OTA (Over-the-Air) update, which means the roll out process will take place in phases. Neurogadget reported AT&T is the only US carrier that hasn't got the approval to release Android 6.0 Marshmallow.

Now, let's check out the Marshmallow rollout on Motorola devices. Moto G (2015) smartphone users from India, Europe and the U.S. got their new firmware. Also, the software upgrade is now available for users of the Moto G (2014) in the US, India and Brazil.

Furthermore, Android Marshmallow landed on an unlocked version of Moto X Pure Edition (2015) in the last quarter of 2015. US mobile carriers like Sprint and Verizon also provided Android upgrade to Moto X Pure Edition (2015) users. Moto X Play owners in Brazil, India and Europe have also enjoyed the upgrade last year.